The present invention relates generally to battery technology, and more particularly, to use of second battery life to reduce CO2 emissions.
Batteries used in electric vehicles cannot be used in the vehicle once the battery capacity falls to 70%-80%. The remaining capacity of these batteries, referred to second life batteries, can be employed in various applications so that they can be kept out of landfills. One of the applications is to use the second life batteries to reduce carbon dioxide (CO2) emissions from the grid. The CO2 emission profile varies depending on the time of the day, month and season. Emissions are high when only the base load plants are operating and low when renewable are used. We charge second life battery during the low emission hours of the day and discharge it when the emissions are high from the grid. With the increase in renewable generation such as photo voltaic, wind energy the carbon foot print changes with the hour of the day. The analysis is to optimize the use of second life battery to reduce the emissions considering uncertainties in the load and availability of renewable power.
Previous research addresses CO2 emissions reduction using hourly data of the emissions from the generators and different fuel types used. They compare the dollar amount saved by emissions avoided and peak demand reduced. However, this prior effort does not account for uncertainties in renewable energy prediction and an initial state of charge (SOC) of the second life battery as the invention does.
Prior works cover peak demand reduction vs. CO2 emission savings using stationary battery storage. One article discusses energy and emission analysis in particular focusing on the dollar value of the emissions avoided compared to the dollar value of the peak demand reduction.
In another prior work, Gaussian probability distribution is used for calculating the initial SOC of a second life battery when it is removed from the electric vehicle and is ready for second use. This process is unique in finding the range of state of charge (SOC) and the probability distribution of having a second life battery with a particular SOC. A similar procedure has been used to forecast errors for wind and load forecast errors.
Accordingly, there is a need for reducing CO2 emissions using a second life battery that takes into account availability of the zero emissions power that takes into account zero emission power uncertainties as well as load profile uncertainties.